Variable choke



Oct. 4, 1938. E. E. DAVIDSON VARIABLE CHOKE Filed May 24, 1937 5. .5.zwwbsom Patented Oct. 4, 1938 UNITED STATES PA Tj ENT-" 'OFFICE2,131,836 7 VARIABLE onokn Edward E. Davidson, Houstonfllex. vApplication May 24,1937, Serial No. 144,384

1 Claim.

flow through a choke so that it will produce only the amount which ithas been determined it should produce.

Previously, it has been the custom to insert the standard choke, or suchother choke as may be decided upon, by removing a bull plug on onebranch of a T or cross, andinserting the choke through the T or crossinto an internally threaded section in the flow line on the opposite,side of such fitting. The bull plug is then replaced and the valvesopened to flow the well.

The difiiculty with the practice just set forth, however, is that inmany instances it is necessary to make numerous and frequent changes inthe size of choke employed in order to cause the well to produce at thedesired rate. This under the previous practice involved shutting downthe well each time by closing the gate valves ahead of the choke,removing the bull plug through which the chokes are inserted, removingthe choke from the flow line, inserting the new choke, and replacing thebull plug. This is a job requiring a considerable length of time andinvolving in each change the necessity for screwing a choke out ofposition and screwing another choke into position within the flow line.In addition to the time and labor involved in making the changes in thechokes under the previous practice, the threads with which the chokesare engaged within the flow lines after many changes in chokes willdeteriorate. until it may become necessary to disconnect the flow lineand replace a section thereof with a new internally threaded part. Inthe past, attempts have been made toprovide variable chokes which couldbe changed without the necessity for replacing the choke within the flowline in order to vary and regulate the. amount offluid produced by thewell.

However, these have for the most part relied upon the principle of theneedle valve in' which the valve is moved by means of threads or thelike toward or away from a seat within the flow line so as to obstructflow past. said seat in a greater or lesser degree as desired. However,when used with high pressure wells it has been found that such apparatuswill cut out very quickly due to the rapid flow therethrough, and

these chokes have not beengenerally used for this reason. I

'It is an object of this invention to provide a variable choke whichwillmake possible a change from one size of choke to another without thenecessity for dismantling any part. of the apparatus, and withoutinvolving any of the defects and shortcomings in the prior artstructures. I r 7 It is a further object of this inventionto provide avariable choke'which may be varied to present a choke o fany given sizewith substantially no loss of time or expenditure of labor.

It is. a further object to provide a variable choke which will not beany more susceptible of cutting out than are the standard chokescustomarily employed.

It is a further object to provide a variable choke, the wearing parts ofwhich may be removed and replaced with a minimum of effort and withoutdismantling the flow lines at any time that replacement may be foundnecessary.

It is a further object of this invention to provide a variable chokewhich may be opened to permit free flow without any choking actionwhatever;

It is a further object to provide a variable choke adapted to receive astandard choke for purposes of testing production.

Qther objects and advantages of this invention will become apparent fromthe following description taken in connection with the accompanyingdrawing, said drawing and descrip tion being by way. of illustration andexample only, and not by way of limitation.

In the drawing:

.Fig. 1 is a vertical cross section illustrating a choke constructed inaccordance with this invention. i

Fig. 2 is'a horizontal cross section taken along the line 2-2 of Fig. 1.g

r Fig. 3 is a vertical cross section at right angles to that shown inFig; 1 taken along the line 3--3 of Fig. 1. V

Fig. 4 is an elevation illustrating the choke shown in Fig. 1 connectedto a portion of a Christmas tree. 7

The choke illustrated in the drawing consists of a body member I ofelongated formation and having a passageway therethrough. At one end,

the body member is externally threaded as illustrated at 2' to receivethe cross 3 forming a portion of a Christmas tree. At its other end, itis formed as illustrated at 4 to receive'a flow line 5.

The upper branch of the cross 3 is closed by means of a bull plug 6 towhich a pressure gauge 1 is connected in the usual manner. The

is provided with a bull plug 8 and the lower portion of the cross isconnected to the portion 9 of the Christmas tree.

The passageway through the body I for the major portion of the length ofthe body is of an elongated cross section as shown at I0. That is, onedimension is substantially twice the other. At-its intake end, however,the passageway is reduced as indicated at II to a cylindrical bore ofsubstantially the same diameter as the shortest dimension of theremainder of the passageway. The outer end of this bore is threaded atI2 to receive a standard choke such as is used in testing the productionof a well to determine the amount it shall be allowed to produce.

Intermediate its ends and intersecting the passageway I0 the body I isformed with a plurality of slightly tapered lateral openings I3 adaptedto receive respectively a series of plug valves which have inthisdisclosure been indicated by the numerals I4 to I8, inclusive. Eachof these plugs has a transverse opening I9 therethrough after the mannerof the customary plug valve, these openings I9 in the various plugsbeing of substantially the same size as the bore II and in alignmentwith that bore and with each other so that when all of the plugs areturned to place their openings I9 in alignment with the passageway I0 asubstantially unrestricted passageway will be provided through the bodyI.

Each of the plugs, however, is provided with a second transverse openingat substantially right angles to the openings I9, these second mentionedtransverse openings being designated by the numerals 20 to 24,inclusive, and varying in size depending upon the sizes of the chokeopenings which it is desired the device shall be capable of providing.As illustrated 'in the drawing, the openings I9 and the bore II are sopositioned as to be in alignment with one side portion of the crosssection of the passageway I0. The openings 20 and 24 inclusive, areoff-set from the openings I9 and are arranged to be in alignment withthe other side portion of the opening Ill.

The external surface of the body I adjacent the open ends of the taperedopenings I3 is provided with a seat 25 adapted to receive a plate orgasket 26 which serves the dual purpose of forming a seal about the openends of the openings I3 and of retaining the plugs I4 to I8, inclusive,in position within the body I. Positioned against the exterior of theelement 2 5 is a fitting 21 held in place by means of screws 28 or thelike and formed with portions 29 providing stufiing boxes adapted toreceive packings 30. These packings 30 are compressed by means of glandnuts 3| so as to provide a seal about the stems 32 of the plugs I4' toI8, inclusive. These plugs may be rotated as desired by means of squaredportions 33 formed on the external ends of the stems 32.

In operation, the well is first connected with the body I in position asillustrated in Fig. 4, and with a standard choke threaded into theopening I2. All of the plugs I4 to I8, inclusive, are rotated so thatthe openings I9 will be in alignment with each other and with theopenings I I and I2. The well is then permitted to flow through thestandard-choke until its capacity is determined and the rate at which itis to be allowed to produce decided upon, The well is then shut down bymeans of gate valves customarily provided (not shown) and the bull plug8 is removed. By means of a suitable wrench provided for the purposewhich is inserted through the cross fitting 3 the standard choke is thenremoved from the threaded opening I2 and taken out through the oppositelateral branch of the cross member from which branch the bull plug 8 hasbeen removed. The bull plug 8 is then replaced and whichever one of theplugs I4 to I8, inclusive, is desired is rotated so that the opening I9therein is at right angles to the passageway I0 and so that the smalleropening 20, 2|, 22, 23 or 24, as the case may be, is placed in alignmentwith the lower portion of the passageway I 0. The well is then openedand allowed to flow.

Assuming that the opening 22 of the plug I6 has been placed in alignmentwith the passageway ID as illustrated in Fig. 1, the well will then bein efiect flowing through a choke of the size of the passageway 22. If,however, it be found that the well flowing through this passageway 22produces oil more rapidly than desired, the plug I1 or the plug I8 maybe rotated so as to place the opening 23 or the opening 24, as the casemay be, in alignment with the passageway Ii], after which the plug I6will be rotated to place the opening I9 in alignment with the passagewayI0. Similarly, if the flow through the opening 22 be found to be tooslow, the plug I4 or the plug I5 may be rotated so as to place theopening 20 or the opening 2I in alignment with the passageway IIJ. Thus,it will be seen that the choke opening provided for the flow of oil orother fluid may be changed at will with substantially no loss of time orexpenditure of labor, and without necessity for shutting down the well.It will further be seen that the number of choke openings available islimited only by the number of plugs provided in the body I, and it willbe appreciated that this number can be varied to provide either more orless plugs than illustrated, fiepending upon the need which may existthere- It will further be appreciated that inasmuch as the chokeopenings provided by this invention are not determined by adjustment,but are predetermined when the openings 20 to 24, inclusive, are formed,there will be no errors introduced due to faulty adjustment such as ispossible with the needle valve type or adjustable choke, and the wearwill be no greater than would exist with the standard choke.

Having described my invention, I claim:

In a choke connection, a body having a relatively large passagewaytherethrough and a plurality of rotatable plugs extending transverselyof and interrupting said passageway, each plug having a relatively largeopening, all of which are of substantially the same size and adapted tobe arranged in alignment with each other to provide a substantiallyunrestricted passage through the connection, and each plug having asmaller opening therethrough at a substantial angle to and off-set fromand independent of the larger opening, said smaller openings being ofvarying sizes in the respective plugs whereby one of said plugs may berotated to move the larger opening out of alignment with. the passagewayand the smaller opening into alignment therewith to provide a selectivepredetermined restriction in said passageway.

EDWARD E. DAVIDSON.

